JPH09288963A - Electric field emission cold cathode array, and picture image display device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To guarantee action even an electric field emission cathode and a gate electrode are short-circuited, by providing a fusing mechanism due to an overcurrent, on at least one side, between a cathode conductor and a first electricity feed wire, and between the gate electrode and a second electricity feed wire. SOLUTION: An electric field emission cathode array substrate 11 is formed of a first electricity feed wire 13a: for flowing an electric current in an electric field emission type cathode 14, and a cathode conductor 13b: formed from the electricity feeding wire 13a via a fusing mechanism 19, on an insulating supporting substrate 12. An electric field emission cold cathode 14 is formed on the cathode conductor 13b, and moreover thereon a second electricity feed wire 15a is formed in a direction, orthogonal to the electricity feed wire 13a via an insulating layer 15. A gate electrode 15b is formed of the electricity feed wire 15a via the fusing mechanism 19. Consequently, when the cathode conductor 13b and the gate electrode 15b are short-circuited, the fusion mechanism 19 is fused by an overcurrent, to cut off a short-circuited portion from the other portion, thereby continuing electron radiation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission cold cathode array and an image display apparatus using the same, and more particularly to a field emission cold cathode array having a redundant mechanism and an image display apparatus using the same.

[0002]

2. Description of the Related Art A field emission type cold cathode can be manufactured by using a fine processing technique used for manufacturing a semiconductor device and has various advantages. Therefore, its use in various fields has been studied. ing. That is, since a filament is not needed, electric power for heat generation is unnecessary as compared with the currently widely used hot cathode, and the number of electrons per unit area is remarkably large.
Because of its simple structure, easy miniaturization and flattening, and excellent environmental resistance, it is attracting interest in various vacuum ICs, microwave vacuum tubes, electron sources for flat panel display devices, and the like. In particular, a field emission display (FED) that uses a field emission cold cathode as an electron source can be a flat image display device with high brightness, no field dependence, and low power consumption. Since then, research and development have been actively carried out.

An example of a conventional FED is shown in FIG. In FIG. 5, (a) is a partial sectional view of the FED, and (b) is the FED.
FIG. 3 is an exploded perspective view of a field emission cold cathode array used in the above. In FIG. 5, reference numeral 31 indicates a field emission cold cathode array substrate. The field emission cold cathode array 31 is
A cathode conductive portion 33 for supplying a current to the field emission cold cathode 34 is formed in a strip shape on an insulating support substrate 32, and is directly or through a resistance layer (not shown) thereon. A field emission cold cathode 34 is formed, and an insulating layer 35 is further formed thereon.
The gate electrode 36 is formed in the shape of a strip in the direction orthogonal to the cathode conductive portion 33. The gate electrode 36 is provided with an opening corresponding to each field emission cold cathode 34.

On the other hand, reference numeral 37 indicates an anode substrate, and a transparent electrode 39 serving as an anode electrode is formed on a transparent insulating substrate 38, on which R (red), G (green), B is formed.
Phosphor layers 40R, 40G, 40B that emit (blue) light
(Not shown). The field emission type cold cathode array substrate 31 and the anode substrate 37 are arranged side by side in parallel by a spacer (not shown) so as to keep a constant distance, the inside is made a high vacuum, and the periphery is sealed by frit glass.

When the voltage is raised to a positive potential on the gate electrode 36 by making 33b of the cathode conductive portion 33 negative, and at the intersection of the cathode conductive portion 33b and the gate electrode 36b. Electrons are emitted from the tip of a certain field emission cold cathode 34b. At this time, if a positive electric potential is applied to the opposing anode substrate 37, for example, when electrons emitted from the tip of the field emission cold cathode 34 collide with the corresponding phosphor layer 40G, G is emitted to display an image. Is possible.

However, in the field-emission cold cathode array as described above, the distance between the field-emission cold cathode 34 and the gate electrode 36 is as small as several μm, and a strong electric field is applied, so that it exists originally in a vacuum. Alternatively, fine dust caused by the field emission type cold cathode array substrate or phosphor particles that have fallen off from the anode electrode may cause the field emission type cold cathode 34 and the gate electrode 3.
There is a problem that if it falls in between 6, a short circuit is likely to occur, and once it is sandwiched, it cannot be easily separated. When such a problem occurs, it causes a fatal problem that electron emission stops in the corresponding pixel, or in some cases, in the entire display, and it is necessary to solve the problem in order to put the FED into practical use.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and even when a field emission type cold cathode and a gate electrode are short-circuited in a part of a pixel, the entire FED is It is an object of the present invention to provide a field emission type cold cathode array capable of ensuring the above operation and an image display device using the same.

[0008]

In order to solve the above problems, the present invention (Claim 1) provides a field emission cold cathode which emits electrons, and a cathode which supplies a current to the field emission cold cathode. A conductive part, a first power supply line for supplying a current to the cathode conductive part, a gate electrode for controlling an electron flow from the field emission cold cathode, and a second power supply for supplying a current to the gate electrode. A power supply line, and at least one of the cathode conductive portion and the first power supply line and between the gate electrode and the second power supply line is provided with a fusing mechanism due to overcurrent. A field emission cold cathode array is provided.

According to the present invention (claim 2), a plurality of gate electrodes in the field emission type cold cathode array according to claim 1 are independently formed in a unit constituting a pixel, and the gate electrodes are independently formed. A feature is that a fusing mechanism due to overcurrent is provided between each formed gate electrode and the second power supply line.

Further, according to the present invention (claim 3), a plurality of cathode conductive parts in the field emission type cold cathode array according to claim 1 are independently formed in a unit constituting a pixel. The present invention is characterized in that a fusing mechanism due to an overcurrent is provided between each cathode conductive portion formed independently and the first power supply line.

According to the present invention (claim 4), the fusing mechanism due to overcurrent in the field emission type cold cathode array according to claim 1 has a cross-sectional area as compared with a wiring or a feeder line made of a low melting point metal or its alloy. The wiring is characterized in that it has a smaller cross-sectional area than that of a wiring having a small size or a power supply line made of a low melting point metal or an alloy thereof.

According to the present invention (claim 5), a field emission type cold cathode which emits electrons, a cathode conductive part which supplies a current to the field emission type cold cathode, and a cathode conductive part are provided. The cathode conductor includes a first power supply line for supplying a current, a gate electrode for controlling an electron flow from the field emission cold cathode, and a second power supply line for supplying a current to the gate electrode. Emission field cold cathode array provided with a fusing mechanism due to overcurrent between at least one of the portion and the first power supply line and between the gate electrode and the second power supply line, and emission from the field emission type cold cathode Provided is an image display device having a phosphor screen which causes the emitted electrons to collide with each other to emit light.

The field emission type cold cathode array according to the present invention is provided between the cathode conductive portion and the first power feed line, and between the gate electrode and the second feed line.
Since a fusing mechanism due to overcurrent is provided in at least one of the power supply lines of 1., when the field emission type cold cathode and the gate electrode are short-circuited, between the cathode conductive part and the first power supply line, and the gate. The fusing mechanism provided on at least one of the electrode and the second power supply line is fused by an overcurrent, and the short-circuited portion is separated from the other portions. Therefore, a normal voltage is applied to the other parts, and electron emission is continued.

In the present invention as described above, the first power supply line for supplying current to the cathode conductive portion and the gate electrode for supplying current to the field emission type cold cathode, respectively. , And second for supplying current to the gate electrode
The provision of the power supply line makes it possible to provide a fusing mechanism due to overcurrent.

In this case, an object of the present invention is to provide a fusing mechanism due to an overcurrent between at least one of the cathode conductive portion and the first power feed line and between at least one of the gate electrode and the second power feed line. Although it is possible to achieve the above, a sufficient effect can be obtained by providing a fusing mechanism on both sides.

When a fusing mechanism due to overcurrent is provided between at least one of the cathode conductive portion and the first power feeding line and between the gate electrode and the second power feeding line, the fusing mechanism is provided. The configuration on the non-existing side may be the same as the conventional configuration, that is, a configuration without a power supply line.

In order to obtain a more preferable effect of the present invention, a plurality of gate electrodes are independently formed in a unit forming a pixel, and each of the gate electrodes is formed independently. It is preferable that a fusing mechanism due to overcurrent is provided between the second power supply line and the second power feeding line.

As shown in FIG. 5, the conventional gate electrode is not formed in a strip shape, but is divided into a plurality of units constituting a pixel, and the gate electrode is divided into smaller units. If the fusing mechanism of the present invention is provided between each gate electrode and the second power supply line, the portion cut off by shorting becomes a unit smaller than one pixel, which is better. That is, a good electron emission can be obtained. For example, when the gate electrode forming one pixel is divided into four parts and independently formed, one gate electrode in the pixel is fused with the second power supply line, and that portion emits light. Even if the state does not occur, since there is no problem in the other three parts, the state that all one pixel does not emit light does not occur.

Further, in order to obtain a more preferable effect of the present invention, a plurality of cathode conductive portions are independently formed in a unit constituting a pixel, and each of the independently formed cathodes is formed.
It is preferable that a fusing mechanism due to overcurrent is provided between the conductive portion and the first power supply line.

This is as shown in FIG.
The cathode conductive portion is not formed in a strip shape, but the cathode conductive portion is formed by a small unit such as a unit forming a pixel, and the cathode conductive portion is provided between each cathode conductive portion and the first power supply line. If the fusing mechanism of the present invention is provided, the portion cut off by shorting becomes smaller, and better electron emission can be obtained. For example, four cathode conductive parts forming one pixel are used.
When configured separately, one of the
Even if the conductive portion and the first power supply line are melted and the part does not emit light, there is no problem in the other three parts, so that the state where all one pixel does not emit light does not occur. .

Further, the fusing mechanism due to overcurrent has a cross-sectional area smaller than that of a wiring made of a low melting point metal or its alloy, a wiring having a smaller cross-sectional area than that of a power feeding line, or a power feeding line made of a low melting point metal or its alloy. The wiring may be made smaller.

The wiring forming the fusing mechanism has a lower melting point than that of the first power feeding line or the second power feeding line, or the low melting point cross-sectional area is made small so as to have high resistance. When an electric current is applied, it can be blown out before each power supply line, and the effect of the present invention can be obtained.

As the low melting point metal or its alloy, Ni-Cr, Cr or the like can be used. In addition, in the image display device including the field emission type cold cathode array, when the field emission type cold cathode and the gate electrode are short-circuited, between the cathode conductive portion and the first power supply line, and between the gate electrode and the second feed line. The fusing mechanism provided on at least one of the power supply lines of fusing melts due to overcurrent, and the short-circuited part is separated from the other part, so that a normal voltage is applied to the other part.
Electron emission is continued and normal image display is possible.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is an exploded perspective view of an FED according to an embodiment of the present invention in a disassembled state.
In FIG. 1, (a) shows an anode substrate and (b) shows a field emission cold cathode array substrate. The field emission type cold cathode array substrate 11 shown in FIG. 1B has a first feeder line 13a for supplying a current to the field emission type cold cathode 14 on an insulating support substrate 12, and this feeder line. From fusing mechanism 1
9 to form the cathode conductor 13b formed,
A field emission type cold cathode 14 is formed on the cathode conductor 13b directly or via a resistance layer (not shown), and an insulating layer 15 is further formed on the field emission type cold cathode 14 in a direction orthogonal to the first power supply line 13. The second power supply line 15a is formed, and the gate electrode 15b is formed from the second power supply line 15a through the fusing mechanism 19.

As shown in the drawing, the cathode conductor 13b and the gate electrode 15b in FIG. 1 are formed in an island shape in small units such as units forming pixels. In FIG. 1, the field emission cold cathode 14 is formed on all the cathode conductors 13b in the same manner, and all the gate electrodes 15b are provided with openings corresponding to the field emission cold cathode 14. There is.

On the other hand, the anode substrate 16 shown in FIG.
Is the ITO that will become the anode electrode on the transparent insulating substrate 17.
A transparent electrode 18 made of, for example, R, G, B
The phosphor layers 1R, 1G, and 1B that emit light are formed.
Field emission cold cathode array substrate 11 and anode substrate 16
Are arranged in parallel in parallel with each other with a spacer (not shown) so as to keep a certain distance, the inside is made a high vacuum, and the periphery is sealed with frit glass.

The manufacturing process of the field emission type cold cathode array substrate 11 thus constructed will be described in detail with reference to FIGS. 2A to 4A are perspective views,
(B) is sectional drawing which extracts and shows a part.

First, for example, a soda-lime glass substrate having a thickness of 1 mm is used as the support substrate 12, and a metal thin film such as Ta or Mo is formed on the support substrate 12 to a thickness of about 100 nm by a known thin film forming technique such as a sputtering method. The thin film is patterned by using a known photolithography method to form the first power supply line 13a and the cathode conductor 13b (FIG. 2). Then, a fusing mechanism 19 made of Ni-Cr, Cr or the like is formed between the first power supply line 13a and the cathode conductor 13b by mask sputtering or photolithography (FIG. 3).

An insulating film 15 made of a SiO ₂ film or the like is formed thereon with a thickness of about 1 μm. On top of that,
Using a known thin film forming technique, a metal thin film made of Ta, Mo or the like is deposited to a thickness of about 200 nm, and this is patterned by using a known photolithography method to form the second power supply line 15a. And the gate electrode 15a are formed. At this time, an opening is formed in the gate electrode 15a so as to penetrate the insulating layer 15 and expose the cathode conductor 13b.

Next, the second power supply line 15a and the gate electrode 15 are formed by mask sputtering or photolithography.
Between b, the fusing mechanism 19 made of Ni-Cr, Cr, etc.
To form Then, a cone-shaped field emission cold cathode 1 made of Mo or the like is formed in a hole penetrating the insulating layer 15 and exposing the cathode conductor 13b by using a known rotary evaporation method.
4 (FIG. 4).

In the field emission type cold cathode array according to this embodiment, the diameter of the bottom of the field emission type cold cathode 14 is 0.8 μm.
m, the height was 0.8 μm, the diameter of the opening of the gate electrode 15a was 1.5 μm, and the distance between the tip of the field emission cold cathode 14 and the gate electrode 15a was 0.2 μm. The field emission type cold cathode array substrate 11 having such dimensions has 10
^-9 Torr high vacuum, gate voltage 85V, 1μA
Although the gate current was normal, the field emission cold cathode 1
4 and the gate current 15a were forcibly short-circuited at one place, it was confirmed that a large current exceeding 10 mA flows, and the fusing mechanism 19 in that portion blows in a short time.

A flat type image display device can be obtained by arranging the phosphor screen so as to face the field emission type cold cathode array described above. In this embodiment, the case where the fusing mechanism due to overcurrent is provided between the cathode conductor and the first power supply line and between the gate electrode and the second power supply line has been described. Conductor and first
The same effect can be expected if the fusing mechanism due to overcurrent is provided between any one of the power feeding lines and between the gate electrode and the second power feeding line.

Further, in this embodiment, the fusing mechanism 19 due to overcurrent is made of a low melting point metal or alloy, and the narrow portion is provided. However, the fusing mechanism 19 is made of a low melting point metal or alloy. Only the passage may be provided, or only the narrow portion of the conductor may be provided.

The structure of the field emission type cold cathode array and the image display device of the present invention is not limited to any other structure as long as it has the fusing mechanism intended in the present invention.

[0035]

As described above, according to the field emission type cold cathode array of the present invention, at least one of the cathode conductor and the first feed line and the gate electrode and the second feed line. In addition, since the fusing mechanism due to overcurrent is provided, when the cathode conductor and the gate electrode are short-circuited, the fusing mechanism is blown by the overcurrent, the short-circuited part is separated from the other, and the other part is normally Is applied, and electron emission continues.

Further, according to the image display device of the present invention, since it is equipped with such a field emission type cold cathode array,
When the field emission type cold cathode and the gate electrode are short-circuited, the fusing mechanism melts due to overcurrent, the shorted part is separated from the other part, and the voltage is normally applied to the other part, so that the electron emission continues. Therefore, the image can be continuously displayed.

Therefore, according to the present invention, the redundancy of the field emission type cold cathode array can be greatly enhanced, and the reliability of various devices including the image display apparatus using the field emission type cold cathode array can be improved. It is possible to significantly improve the sex.

[Brief description of drawings]

FIG. 1 is a perspective view showing a field emission cold cathode array according to an embodiment of the present invention.

FIG. 2 is a perspective view and a cross-sectional view showing a field emission type cold cathode array manufacturing process according to an embodiment of the present invention.

FIG. 3 is a perspective view and a cross-sectional view showing a field emission type cold cathode array manufacturing process according to an embodiment of the present invention.

FIG. 4 is a perspective view and a cross-sectional view showing a field emission type cold cathode array manufacturing process according to an embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional field emission display and an exploded perspective view showing a field emission cold cathode array.

[Explanation of symbols]

11 ... Field emission type cold cathode array substrate, 12 ... Support substrate,
13a ... 1st feeder, 13b ... Cathode conductor, 14
Field emission type cold cathode, 15 ... Insulating layer, 15a ... Second feeder, 15b ... Gate electrode, 19 ... Fusing mechanism.

Claims (5)

[Claims] 1. A field emission cold cathode that emits electrons, a cathode conductive portion that supplies a current to the field emission cold cathode, and a first power supply line that supplies a current to the cathode conductive portion. A gate electrode for controlling an electron flow from the field emission cold cathode, and a second power supply line for supplying a current to the gate electrode, and the cathode conductive portion and the first power supply line are connected to each other. A field emission type cold cathode array characterized in that a fusing mechanism due to overcurrent is provided in at least one of the space and between the gate electrode and the second power supply line. 2. A plurality of the gate electrodes are independently formed within a unit forming a pixel, and an overcurrent is generated between each of the independently formed gate electrodes and the second power supply line. The field emission cold cathode array according to claim 1, further comprising a fusing mechanism. 3. A plurality of the cathode conductive portions are independently formed within a unit forming a pixel, and each of the cathode conductive portions and the first power supply line are independently formed. The field emission cold cathode array according to claim 1, further comprising a fusing mechanism for overcurrent. 4. The melting mechanism due to the overcurrent is cut in comparison with a wiring made of a low melting point metal or an alloy thereof, a wiring having a smaller cross-sectional area than a feeding line, or a feeding line made of a low melting point metal or an alloy thereof. The field emission type cold cathode array according to claim 1, which is a wiring having a small area. 5. A field emission cold cathode that emits electrons, a cathode conductive portion that supplies a current to the field emission cold cathode, and a first power supply line that supplies a current to the cathode conductive portion. A gate electrode for controlling an electron flow from the field emission cold cathode, and a second power supply line for supplying a current to the gate electrode, between the cathode conductive part and the first power supply line. ,
And a field emission type cold cathode array having a fusing mechanism due to overcurrent on at least one of the gate electrode and the second power supply line, and a phosphor screen for causing electrons emitted from the field emission type cold cathode to collide and emit light. An image display device comprising: